1. Field of the Invention
The present invention relates to a drum type indication system which searches a signal line producing a detection signal out of a plurality of signal lines and indicates an indication item relating to the detected signal line.
2. Description of the Prior Art
Prior art methods for detecting normal or abnormal function of various components of an automobile or the like and indicating the results include a method in which as many indication items as the number of items to be detected and illumination lamps for illuminating those items are arranged in a plane and a selected lamp is lit to illuminate a selected item, and a method in which a plurality of transparent acrylic plates each having an indication item engraved thereon are laminated and each of the plates is selectively illuminated by an illumination lamp provided for each of the plates to indicate a selected detection item.
However, those prior art methods have the following disadvantages. Namely, the former method of arranging as many indication lamps as the number of items to be detected requires a relatively large indication area and the latter method of laminating the transparent acrylic plates and illuminating a selected one of them by the lamp has a drawback in that one cannot easily view the indicated item because a light directed to an inner indication plate leaks to an outer indication plate so that the indication item on the unselected outer indication plate is also illuminated more or less.